Bumblebee Bat

Kitti's hog-nosed bat measures approximately 29–33 mm (1.1–1.3 in) long and weighs around 2 g (0.071 oz), earning its common name "bumblebee bat". It is the smallest bat species and potentially the world's smallest mammal by body length, though this distinction depends on the measurement criteria used. The main competitors for the title are small shrews; in particular, the Etruscan shrew may be lighter at 1.2 to 2.7 g (0.042 to 0.095 oz) but its body is longer, measuring 36 to 53 mm (1.4 to 2.1 in) from its head to the base of the tail.

The bat has a distinctive swollen, pig-like snout with thin, vertical nostrils. Its ears are relatively large, while its eyes are small and mostly concealed by fur. In the jaw, the premaxillae are not fused with surrounding bones, and the coronoid process is significantly reduced. Its teeth are typical of an insectivorous bat. The dental formula is 1.1.1.32.1.2.3. The upper incisors are notably enlarged. The bat's upperparts are reddish-brown or grey, while the underside is generally paler. The wings are relatively large and darker in colour, with long tips that allow the bat to hover. The second digit of the wing is made of a single short phalanx, and the humerus has an increased number of locking tubercles on its head and beyond. …

Kitti's hog-nosed bat occupies limestone caves along rivers within dry evergreen or deciduous forests. In Thailand, it is restricted to a small region of the Tenasserim Hills in Sai Yok District, Kanchanaburi Province, within the drainage basin of the Khwae Noi River. While Sai Yok National Park in the Dawna Hills contains much of the bat's range, some Thai populations occur outside the park and are therefore unprotected. Since the 2001 discovery of a single individual in Myanmar, at least nine separate sites have been identified in the limestone outcrops of the Dawna and Karen Hills outside the Thanlwin, Ataran, and Gyaing Rivers of Kayin and Mon States. The Thai and Myanmar populations are morphologically identical, but their echolocation calls are distinct. It is not known whether the two populations are reproductively isolated.